Method of improving brightness of fibrous materials



Patented Feb 8,

METHOD OF IMPROVING BRIGHTNESS OF FIBBOUS Felix Axel'rad, New York, N. Y., assignmto The Richards Chemical Works, Jersey City, N. L,

a corporation of New Jersey No Drawing. Application May 18, 1940, Serial No.

4 Claim.

This invention relates to the treatment of tex- In Austria March 19, 1936 tile materials, paper, leather, and the like, in

order to render the same bright and brilliant.

The invention is directed to the impregnation of such materials with substances which do not have definite dyeing or coloring properties. The basis of the present invention is a process for the improvement of such materials as textile fibers and fabrics paper and similar materials, leather, finishes suitable for the treatment of said materials, and the like, by the application of substances which render the combination of material and substance capable, under the action of light, of emitting light of predetermined wavelengths. By the application of such substances to textiles, leather and the like, either undyed or dyed, a marked improvement is obtained in the clearness and the brightness of the materials.

In the case of undyed materials, application of suitably selected members of the aforesaid class of substances renders the same brighter and apparently considerably whiter. In the case of dyed materials, there is obtained a more brilliant color and an accentuation of the color tones; The substances used herein may be called photoluminescent substances which are-capable of emitting light, and the term is-intended to include phosphorescent and fluorescence.

Such photoluminescent substances are used which in themselves have very little or no color and are generally incapable of imparting definite color to the materials treated therewith and which are applicable in small quantities. Thereby, the basiccolor or tone of the dyes used in the materials is not changed and the purity or clarity of the dye is not adversely affected.

There are various important applications of the present invention, as for instance in the making of suede leather. The production of such leather in brilliant pastel shades has been considered quite difficult. Also, it'has been extremely difllcult to obtain a suede leather in which the dye was a deep black giving a blue-black shimmer. As ordinarily made, such leather is not sufiiciently black but is usually a brownish black or is so laden with dyes that upon rubbing of the leather the dye is physically removed. By the applicationof photoluminescent substances in accordance with the present invention, especially such substances which'tendto emit blue rays, this difficulty has been completely removed and the leather has a brilliant blue-black color without any tendency to removal of the dye by rubbing. be treated in accordance with the present invention. 7

Another important effect obtainable by th use of photoluminescent substances is in connec- Similarly, other. dyed leathers may substances, one may obtain the emission of white light from the treated materials, such light approaching that of the natural white light, and, in fact, the color of such treated materials approaches the color of pure snow. The combination of the hotoluminescent substances can be such that where the material being treated has a residual color, usually yellowish, this may be compensated for by, for instance, a bluish phosphoresent substance or the like.

A further advantage in the application of photoluminescent substances is that one may use higher concentrations thereof while still obtaining the desired maximum effect of brightening the material, whereas if one attempts to obtain a brightening by the use of an excess of dyes, a defective dyeing of the material results. By such application of said substances, various attractive effects may be obtained, such as iridescent, mother-of-pearl, damask, and the like. The application of the photoluminescent substances may be by printing the material therewith, applying the same to certain of the threads or fibers which are afterwards made into the fabric, and several such substances may be used in the partial treatment of fabrics to obtain various desired efiects. Thereby, one may obtain diflerent light effects depending upon the angle from which the material is viewed, or depending upon I whether daylight or artificial light of various kinds is applied.

The substances may be applied in various ways. The solubility thereof in water or organic solvents is not at all essential, although it is quite convenient to work with soluble materials. Also, in order to obtain a lasting effect, it is desirable that the photoluminescent substances be fixed onto the material, which can be done in various ways. For instance, one may apply cation active products to the materials, said products having positively charged adsorbable ions with characteristic groups making the products adsorbable by fibers and being able to precipitate and bind the generally negative charged photoluminescent particles by aid of molecular-electric powers uniformly and fast on the fibers. Various substances of this kind may be used, as for example cetylpyridiniumbromide, and laurylpyridiniumlaurat. When insoluble photoluminescent substances are used, these may be introduced into the materials by a suitable binding material, as for example by the fixing into the materials being treated by means of a synthetic resin formed in situ.

For instance, one may make a mixture of urea and formaldehyde and mix the insoluble photoluminescent substance therewith, apply the mixture to the material, and thereafter heat the mixture to form a urea-formaldehyde resin within the fiber, and thus permanently fix said "s ubvegetable gums, resins, pigments, dyes, and the,

like. Such additions may be made at the same time as the application of the photoluminescent substances, or independently thereof.

The photoluminescent substance may be present in the material in very small amounts. In all cases, the proportion thereof is considerably less than 1%, say about .1%, and it is usual that such substances are present in the ratio of 1 to- 10,000 by weight. In other words, the amount may be of the order of .01%. Even less may be used, depending on the amount of brightening desired.

The source of such substances is varied and, for example, may be obtained from plants. Among such sources are the bark of the horse chestnut tree (Esculus hippocastanum) the bark of the quinine (Cinchomt ledaeriana), the root of Scopolia japonica, the seeds of Euphorbia and then softened with fat liquor. There is provided a solution having, the following ingredients:

, A black aniline dyestuff -grams An extract of Esculus hippocastanumndonu 40 Methanol liiers 1 The extract is prepared as follows: Bark of Esculus hippocastanum' is extracted with boiling water and the extract treated with lead acetate and filtered. The lead is precipitated from the filtrate with H28 and the filtrate evaporated a low temperature.

until the solution is of syrup" consistency. The leather is sprayed with the solution, the liquid allowed to dry into the leather, and the spraying repeated, if necessary. Thereafter, the leather is drummed once more without water and dried at As a result, the suede leather has a brilliant blue-black color which will not lathuris, the calyx of the willow tree blossom (Salix) the sap of various species of mushroom, seaweed, lichens, milkweed, and the like. The extracts of these plants may be used in crude form or purified. Also, the efficacious substances as for instance esculin, .qulnine, scopoletin, chrysatropa acid may be isolated and used.

Numerous synthetic organic compounds 'are also applicable, as for example anthracene and its derivatives, such as 9-phenyl anthracene, anthracene 1.5 disulphonic acid, 9.10 dichloranthracene disulphonic acid, phenanthrene, pyrene, dihydronaphthene, menthyl salicylate, 3- hydroxy B-methoxy fiuorane, and the like. Compounds and derivatives of cinnamic acid, including the soluble salts thereof, are likewise very active. Among such derivatives are hydroxy, alkoxy, amino and alkyl amino cinnamic acids. Also applicable are anhydrides and lactones thereof. The following are specific examples of certain compounds of this group: z-hydroxycinnamic acid; 2-amino-cinnamic acid; 2.4-hydroxy 5-methoxy-cinnamic acid; 'l-hydroxy 4- methyl-cumarin; and 'l-dimethylamino 4-methyl-cumarin.

The purity of the aforementioned substances is of great influence on the color of the emitted light. The purity of the products depends on the choice of raw material, by which differently emitting substances can be obtained. This possibility of producing different substances, capable of emitting light of difierentcolors, belonging to the same chemical individuals, can be realized in the sense of the invention, especially in the making of white goods where the white light is a combination of spectral colors.

The following are specific examples of the application of photoluminescent substances in accordance with the present invention:

Example I Leather is prepared as usual and dyed with a rub'ofl'.

-' Emmple II An undyed and bleached cotton sheet is treated with a solution containing the following ingredients:

\ Sodium salt of 2.4-hydroxy 5-methoxy-cinnamic acid grams 0.1 Lauryl-pyridinium 1aurate do 0.5 Water liters 1 The cotton sheet is placed in the aforesaid solution held at a temperature of 50 C. for 30 minutes, removed therefrom, rinsed and dried as usual. Upon a comparison of the original cotton sheet and the treated cotton sheet, there is a suitable black dye. It is then dried, damped vast difference in the apparent color thereof since the treated material appears remarkably brighter and more brilliant.

Example III Artificial silk fiber in the form of a hank is Sodium salt of anthracene 1.5 disulphonic acid Water 600 The-material is dipped in the bath and thereafter dried at 70 C. for 10 minutes. It is placed in an oven, held at a temperature of 103 C. for 7 minutes, whereby a reaction is caused to take place to form an insoluble urea-formaldehyde resin in the fiber. The luminescent substance exerts its full effect even though it is incorporated with the resin. At the same time, the resin imparts non-wrinkling propertiesto the product.

' Example IV A sheet of paper which is a mixed sulphite pulp and rag paper ls'treated with the following bath: 3

Ammonium salt of '7-hydroxy-4-methyl cumarin grams'. 1 Water mare 1 The treatment may take place in various ways. The paper sheet may be passed through the bath for about one minute at 20 C. and thereafter dried. Or, the paper pulp just prior to formation into a sheet is mixed with said bath and the photoluminescent substance incorporated in said pulp, and thereby in the paper as it is beingformed. It is also possible to provide a spray of the bath and spray the same onto the paper on the paper making machine prior to the passage of the same to the drying rolls. The bath may also be incorporated in sizing or in phenol materials which are then applied to the paper in the usual manner.

The invention combines specific materials with corresponding substances to give .the desired brilliance, brightness and .cleamess of tone. Naturally, one must select the proper combinations thereof to insure the best results, and both the character and amounts thereof must be gauged so that the combination gives the desired result, which is not to produce phosphorescent textiles, leather or the like, but to cause a sufficient photoluminescence to brighten the treated material. The substances used need not in themselves be fluorescent as many substances used herein are not fluorescent in the solid state nor in concentrated solutions. However, after being combined with the material, some change takes place and photoluminescence is obtained. The substances used do not have any substantial dyeing efiects. However, for instance, in a white fabric which has say a yellowish or reddish cast, the substance may be one which imparts a bluish photoluminescence, such as suitable organic or inorganic phosphorescent substances, to neutrallze the color.

Also, the treatment may be employed to replace bleaching operations, at least in part. It is customary to give white textiles two bleaches. The second may be replaced by using one o! the above substances and, in some cases, all bleaching may be replaced thereby. In the case 01 materials having both white and colored portions where the white still requires further bleaching, no other method is available than that described herein for so treating the white without adversely affecting the colored portions. In fact, by the present invention the colored portions are also improved. In the making of white leather, the complicated white finishing operations may be replaced at least in part by the present treatment.

The amount of substance applied may vary within wide limits. An excess is usually not detrimental but the cost is unnecessarily increased. When a deficiency is used, the efi'ect is not the optimum.

What I claim is:

1. The method of improving the clearness and brightness or fibrous materials deficient in light reflecting properties under ordinary visible light which comprises treating the same with a small fraction of 1% of an organic substance emitting light of predetermined wave length under ordinary visible light, said predetermined wavelength being selected to compensate for the deficiency of reflected light of the material treated by emitting light oi a wave length missing in the reflection spectrum of the untreated material under ordinary visible light.

2. The method or improving the clearness and brightness of fibrous materials deficient in light reflecting properties under ordinary visible light which comprises treating the same with a small fraction of 1% of an organic substance emitting light of predetermined wave length under ordinary visible light, said predetermined ,wave length being selected to compensate for the deficiency of reflected light or the material treated by emitting light of a wave length missing in the reflection spectrum of the untreated material under ordinary visible light and fixing the substance on the fibrous material to'give a product of substantially permanently improved clearness and brightness.

3. The method of improvingthe color tones of dyed fibrous materials deficient in light reflecting properties under ordinary visible light which comprises treating the same with a small fraction or 1% of an organic substance emitting light of predetermined wave length under ordinary visible light, said predetermined wavelength being selected to compensate for the deficiency of reflected light of the dyed fibrous materials by emitting light or a wave length or which the untreated material is deficient under ordinary visible light.

4. The method or improving the color tones of dyed fibrous materials deficient in light reflecting properties under ordinary visible light which comprises treating the same with a small fraction or 1% or an organic substance emitting light 01 predetermined wave length under ordinary visible light, said predetermined wave length being selected to compensate for the deficiency of reflected light of the dyed fibrous materials by emitting light or a wave length of which the untreated material is deficient under ordinary visible light and fixing the substance on the fibrous material to give a product or substantially permanently improved color tones.

' FELIX Ant-RAD. 

